Hi Admin Group!
If any of you use
#Marketing Cloudcould you help me with Upvoting this topic?
The
#Individual Emails Resultsin Salesforce does not transfer to the contact when a lead is converted. This seems very silly. When we convert the lead and create an opportunity our sales reps can no longer see what emails they engaged with when preparing to meet with that potential customer.
Please Upvote this topic!
https://ideas.salesforce.com/s/idea/a0B8W00000Gdhu3UAB/do-not-lose-email-tracking-history-ier-when-converting-lead-to-contact
#Email Marketing #Marketing Cloud Engagement
Lukas Lunow (NoA Ignite) 
Forum Ambassador
I admit this should not be expected behavior, but it is. And looking at Data Cloud taking over this type of data consolidation, I will most probably expect SF to point you in that direction, and create identity resolution across the old lead and new contact.
Should you rely purely on Sales Cloud and Marketing Cloud, I will recommend you following this simple guide for integrating SFMC data to Sales Cloud. Using a simple SQL query, you can do same consolidation in SFMC, and present it in the custom LWC:
https://digitalmarketingoncloud.com/projects/showing-sfmc-data-in-sales-cloud/